YARA · Malpedia signator rules
MALPEDIA_Win_Jssloader_Auto
autogenerated rule brought to you by yara-signator
MalwareJssloaderMalpedia signator rulesCreative Commons Attribution-ShareAlike 4.0Compiles with YARA-X
- Author
- Felix Bilstein - yara-signator at cocacoding dot com
- Date
- 2026-05-04
- Modified
- 2026-05-18
- Score / Quality
- 75 / 75
What this rule detects
autogenerated rule brought to you by yara-signator
Associated malware family: Jssloader.
It defines 10 patterns (0 text, 10 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
win-jssloader-auto.yarCreative Commons Attribution-ShareAlike 4.0
rule MALPEDIA_Win_Jssloader_Auto : FILE
{
meta:
= "autogenerated rule brought to you by yara-signator"
= "Felix Bilstein - yara-signator at cocacoding dot com"
= "c2dfb866-307f-54fc-a93b-1459534d3593"
= "2026-05-04"
= "2026-05-18"
= "https://malpedia.caad.fkie.fraunhofer.de/details/win.jssloader"
= "https://github.com/malpedia/signator-rules//blob/c901f97b7df03e41917da74c2a84b04c227316c2/rules/win.jssloader_auto.yar#L1-L122"
= "N/A"
= "0c3f13c685066a735b5bd23ece29387da4f47270047d27c85f2f68d54bf6b421"
= 75
= 75
= "FILE"
= "1"
= "yara-signator v0.6.0"
= "callsandjumps;datarefs;binvalue"
= "20260422"
= "a182e35da64e6d71cb55f125c4d4225196523f14"
= "20260504"
= "CC BY-SA 4.0"
= "TLP:WHITE"
strings:
$sequence_0 = { 83f81f 0f8703060000 51 56 e8???????? 83c408 c745d800000000 }
$sequence_1 = { 8b4804 8d41f8 89840d70feffff 8d85dcfeffff }
$sequence_2 = { 68???????? c78568fdffff00000000 c7856cfdffff0f000000 c68558fdffff00 e8???????? c645fc16 }
$sequence_3 = { 64a300000000 8b4508 89859cfeffff 8985b8feffff }
$sequence_4 = { 8d8da0feffff c785b0feffff00000000 c785b4feffff0f000000 c685a0feffff00 e8???????? 8d85a0feffff }
$sequence_5 = { 8b45fc 8b7008 8b5004 8b08 c7400800000000 c7400400000000 }
$sequence_6 = { 8d8d20ffffff 6a06 68???????? c78530ffffff00000000 c78534ffffff0f000000 c68520ffffff00 e8???????? }
$sequence_7 = { 7408 8817 47 897de8 }
$sequence_8 = { 51 6a01 6a00 68???????? 52 ff15???????? 8d4b04 }
$sequence_9 = { 8b04bd701d4400 834c0318ff 33c0 eb16 e8???????? c70009000000 e8???????? }
condition:
7 of them and filesize < 581632
}
Strings (10 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $sequence_0 | hex | { 83f81f 0f8703060000 51 56 e8???????? 83c408 c745d800000000 } | |
| $sequence_1 | hex | { 8b4804 8d41f8 89840d70feffff 8d85dcfeffff } | |
| $sequence_2 | hex | { 68???????? c78568fdffff00000000 c7856cfdffff0f000000 c68558fdffff00 e8???????? c645fc16 } | |
| $sequence_3 | hex | { 64a300000000 8b4508 89859cfeffff 8985b8feffff } | |
| $sequence_4 | hex | { 8d8da0feffff c785b0feffff00000000 c785b4feffff0f000000 c685a0feffff00 e8???????? 8d85a0feffff } | |
| $sequence_5 | hex | { 8b45fc 8b7008 8b5004 8b08 c7400800000000 c7400400000000 } | |
| $sequence_6 | hex | { 8d8d20ffffff 6a06 68???????? c78530ffffff00000000 c78534ffffff0f000000 c68520ffffff00 e8???????? } | |
| $sequence_7 | hex | { 7408 8817 47 897de8 } | |
| $sequence_8 | hex | { 51 6a01 6a00 68???????? 52 ff15???????? 8d4b04 } | |
| $sequence_9 | hex | { 8b04bd701d4400 834c0318ff 33c0 eb16 e8???????? c70009000000 e8???????? } |
Condition
7 of them and filesize < 581632In plain words (Heuristic)
- The file must be smaller than 581632 (a cheap guard that skips large files).
- At least 7 patterns in the rule must match.
Test this rule in your browser
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Licence & attribution
Author: Felix Bilstein - yara-signator at cocacoding dot com
Source repository: Malpedia signator rules @ c901f97b7d
Licence: Creative Commons Attribution-ShareAlike 4.0 (repository licence)
Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.
Rule id: c2dfb866-307f-54fc-a93b-1459534d3593
Metadata
| version | 1 |
|---|---|
| tool | yara-signator v0.6.0 |
| signator_config | callsandjumps;datarefs;binvalue |
| malpedia_rule_date | 20260422 |
| malpedia_hash | a182e35da64e6d71cb55f125c4d4225196523f14 |
| malpedia_version | 20260504 |
| malpedia_license | CC BY-SA 4.0 |
| malpedia_sharing | TLP:WHITE |
Tags:FILE
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